fix(#3489): name anonymous arrow function in quickstart eslint config (#3504)

Convert the anonymous arrow function export in
eslint.frontend-shared.cjs to a named function expression
(`createEslintConfig`) to satisfy SonarQube rule javascript:S7726.
This follows the same pattern used in the theme and other workspaces.

Closes #3489

Co-authored-by: fullsend-code <278716306+fullsend-ai-coder[bot]@users.noreply.github.com>

Author: fullsend-ai-coder[bot]

workspaces/quickstart/eslint.frontend-shared.cjs

@@ -36,8 +36,9 @@ const materialUiMigrationEslintConfig = {
 /**
  * ESLint config for frontend packages in this workspace (MUI v4 migration guards).
  */
-module.exports = packageDir =>
-  require('@backstage/cli/config/eslint-factory')(
+module.exports = function createEslintConfig(packageDir) {
+  return require('@backstage/cli/config/eslint-factory')(
     packageDir,
     materialUiMigrationEslintConfig,
   );
+};